1. Field of the Invention
The present invention relates to toner cleaning systems for electrophotographic equipment and, more particularly, to controlling the air flow within the cleaning chamber that contains the cleaning brush and detoner mechanism.
2. Description Relative to the Prior Art
Electrophotographic equipment employs a process for transfer of images that typically use marking particles to form the transferred image. Very commonly, the marking particles are placed on a photoconductor surface (such as a photoconductive drum) using toner as the marking particles. A cleaning process is employed after the image has been transferred to remove excess toner. The cleaning process conventionally employs a cleaning brush having either conductive-core fibers or non-conductive fibers, each of which present their own, individual set of problems. More conventional fur brush (conductive base) types of cleaning systems typically have conductive exterior portions with non-conductive cores. These fur brush based cleaning systems typically do require vacuum supply systems. In conductive-core fiber brush cleaning systems, the exterior of the cleaning brush fibers is non-conductive while the interior core is conductive. In these conductive core based systems, the toner is typically removed from the photoconductor surface by mechanical and electrostatic forces. The toner is then extracted from the cleaning brush by the electrically biased detoner roller. Vacuum supply systems are not needed to remove toner from the photoconductor surface to a waste receptacle in conductive core based systems.
Conductive core based cleaning systems provide advantages in the elimination of the vacuum systems yielding a reduction of system cost, noise levels and power requirements over conventional fur brush cleaning systems. There are also shortcomings in toner particles being thrown from the rotating cleaning brush, or other sources within the cleaning station and drifting out of the housing contaminating other areas of the copier. Accordingly, from the foregoing discussion it should be apparent that there remains a need within the art for a system that provides increase control over airborne toner particles without the need for a vacuum.
This present invention provides a means of reducing and controlling air circulation in cleaning station housings for systems not having a vacuum. The problem of machine contamination by marking particles (such as toner) that are airborne, escaping from the cleaning station is addressed by the method and apparatus of the present invention, wherein the level of airborne toner is greatly reduced. Within the cleaning station, there are two mechanisms that produce air motion. The first involves the moving surfaces of the cleaning brush and detoner roller, is xe2x80x9cdragxe2x80x9d as air near the surfaces moves in the direction of rotation of the cleaning brush and the detoner roller. This is a well-known aerodynamic phenomenon, resulting from the viscous property of air. The second mechanism involves the compression and expansion of the cleaning brush nap as it engages the photoconductor surface and the detoner roller.
As will be shown in the following description, the method and apparatus of the present invention uses these two mechanisms to generate favorable airflow patterns in and around the cleaning station assembly. This and other features are provided by a cleaning system for an electrostatographic reproduction system having a photoconductive drum partially within the cleaning system housing, with a cleaning brush having conductive core fibers within the cleaning system housing contacting the photoconductive drum, and a detoner roller within the cleaning system housing contacting the cleaning brush. The cleaning system housing is provided with ports that allow for air to enter of leave the cleaning system housing. A curved deflector plate is positioned on a side of the cleaning enclosure where the cleaning brush fibers are moving towards the detoner roller. The cleaning system is preferably designed such that the ratio of engagements of the detoner roller to the cleaning brush compared to that of the toner bearing surface to the cleaning brush, is essentially three to one.